NEW DELHI: The current outbreak of lumpy skin disease (LSD) virus, which has spread to almost 15 states and has affected 18.5 lakh bovine animals in the country, is distinct from the virus that was prevalent in India in 2019, said the latest study, adding that 47 unique variants were found in the current version of the fatal viral disease that has killed over 80,000 cattle.
The study, conducted by scientists at the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB) and the State Disease Diagnostic Centre, Jaipur, has said that as genome sequencing has found that the current outbreak in India has a distinct lineage of the virus and to "characterise circulating strains," “it is essential for early detection of the disease as well as for formulating interventions for disease control."
Although previously confined to regions within Africa, the fatal viral disease has caused significantly large outbreaks in many areas of the world in recent years. In 2019, an episode of the disease was reported from India with low rates of morbidity and no reported mortality.
However, the ongoing outbreak of LSDV has spread to various states and has resulted in the mortality of over 80,000 cattle, including cows, over a short period of three months.
According to Sridhar Sivasubbu, senior principal scientist, CSIR-IGIB and one of the scientists associated with the genome sequencing study, “We have found that the samples sequenced by IGIB have distinct differences when compared with the genomes globally available or those that were sequenced in 2019."
“There are 47 unique variants in this current version of the lumpy skin disease virus which has not been documented before,” he told this newspaper.
The scientists analysed five animals with symptoms of the contagious viral disease and compared genomes of the virus extracted from them.
“Our sample size is small, but we have to start somewhere. Yes, there is a distinct difference in the virus, so attention should be paid to it more closely. We will need large-scale genomic surveillance,” he added.
“Due to the limited number of genome sequences available for LSDV, the source of the outbreak could not be traced, further suggesting that additional genomes for the virus could help uncover potential outbreaks and connect existing outbreaks that are unrelated,” said the authors Lenin Bhatt, Rahul C. Bhoyar, Bani Jolly, Ravi Israni, Harie Vignesh, Vinod Scaria, and Sridhar Sivasubbu in the study, which appeared in the preprint server for biology Bioarxiv. It is yet to be peer-reviewed.
“Analysis of the viral sequences suggests the genomes from the 2022 outbreak harbour many genetic variations compared to the reference genome and form a distinct lineage,” they added.
As India is the largest producer of milk in the world, the spread of LSD across the cattle population in India thus has devastating effects on the rural economy and the livelihoods of dairy farmers, the study added.
The outbreak has also caused concerns about milk production. With a production of about 210 million tonnes, India is the largest producer of milk in the world. The country is also seeing the fastest growth in production at 6 per cent, while production growth at the global level is just 2 per cent.
“Although other capripoxvirus infections, including sheep pox and goat pox, are endemic in India, LSDV infections were considered to be constrained to the Sub-Saharan African region till 1981. As the virus continues to spread and evolve, genomic characterisation of LSDV is thus useful for understanding the epidemiology and evolution of the virus,” the study said.
FAQ
What is a lumpy skin disease virus?
The fatal virus mainly affects cows, buffaloes and deer. The United States Department of Agriculture defines Lumpy skin disease (LSD) as a deadly viral disease which spreads when cattles come in direct contact with vectors like mosquitoes, lice, wasps, flies and ticks or through contaminated fodder and water. The outbreaks of LSD occur during warm, wet weather, while the disease usually diminishes in the cooler winter months. It is not a zoonotic virus, so it cannot be transmitted to humans.
How many states are impacted?
LSDV has been reported in various states, but the worst affected are Rajasthan, Gujarat and Haryana. The other states include Andaman and Nicobar Islands, Himachal Pradesh, Punjab, Uttarakhand, Madhya Pradesh, Jammu and Kashmir, Uttar Pradesh, Maharashtra and Goa.
What are the symptoms?
The symptoms include the appearance of nodules on the skin, general malaise, ocular and nasal discharge, fever, and a sudden decrease in milk production. The other symptoms are swelling of peripheral lymph nodes, loss of appetite, and watery eyes, and death. According to the United Nations Food and Agriculture Organisation (FAO), the incubation period or the time between infection and symptoms is about 28 days. As the vaccine is yet to be produced, authorities in India are distributing the goat pox vaccine.
Is it safe to consume milk?
According to officials, it is safe to consume milk from infected cattle as it is a non-zoonotic disease. However, milk production gets affected in the infected animal, depending on the severity of the illness and the immunity level of the animal.
Is there a vaccine developed for lumpy skin disease?
On August 10, India launched the indigenous vaccine Lumpi-ProVac to protect livestock from the viral disease. The vaccine has been developed by the National Equine Research Center, Hisar (Haryana), in collaboration with the Indian Veterinary Research Institute, Izzatnagar (Bareilly). Currently, the government is providing goat pox vaccines to prevent the disease from spreading.